Laminated core with a termainal connector and retainer means



June 4, 1968 E. CZERNOBIL 3,387,245.

LAMINATED coRE WITH A TERMINAL CONNECTOR AND RETAINER MEANS Filed Aug. 30, 1963 5 Sheets-Sheet 1 INVENTOR.

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June 4,' 1968 E. CZERNOBIL 3,387,245

LAMINATED CORE WITH A TERMINAL CONNECTOR AND RETAINER MEANS Filed Aug. 50, 1963 3 Sheets-Sheet 2 INVENTOR.

June 4, 1968 ECZERNOBH. 3,387,245

LAMINATED CORE WITH A TERMINAL CONNECTOR AND RETAINER MEANS Filed Aug. 30. 1963 3 Sheeta-Sheet a INVENTOR.

(Eugene ce'emozz SLMBM I CL 4 @7'57 United States Patent M 3,387,245 LAMINATED CORE WITH A TERMINAL CONNECTOR AND RETAINER MEANS Eugene Czernobil, Chicago, Ill., assignor to Advance Igransformer Co., Chicago, 11]., a corporation of Continuation-impart of application Ser. No. 168,952, Jan. 26, 1962. This application Aug. 30, 1963, Ser. No. 305,592

8 Claims. (Cl. 336192) This application is a continuation-in-part of my copending application for Letters Patent of the United States, Ser. No. 168,952, filed Jan. 26, 1962, for the invention entitled, Combined Retainer and Terminal Connector Mounting Means for Electromagnetic Devices, now abandoned.

This invention relates generally to electromagnetic devices such as ballasts, transformers, and more particularly, concerns the provision of a non-metallic retainer ring for clamping the core and coil elements of said devices in rigid assembly. The invention further contemplates the provision of electrical terminal connector means adapted to be mounted on said retainer ring where-by to facilitate the connection of leads to said electromagnetic device.

Electromagnetic devices of the character described generally comprise a core and coil assembly, including an iron core formed of laminations of electrical sheet steel and at least one electrical coil or winding mounted on said core. The iron core is most commonly in the configuration of a shell structure having an outer elongate rectangular frame-like portion and a central winding leg portion ex tending between the bridging ends of the outer portion. The electrical coils or windings are mounted on the central winding leg between the said bridging ends and disposed in windows formed between said central and outer portions. Said electrical coils or windings are provided with wire extensions and, in some instances, electrical taps, which are adapted to be connected in electrical circuit arrangements. Such extensions may be referred to as coil ends when reference to the starts and/ or ends of the windings is intended and as taps when intermediate wires are drawn out from the coil at certain predetermined locations so as to enable varying numbers of winding turns to be utilized in circuit variations. Lead means are also provided to enable the device to be connected in circuit relationship with a load. Terminal means including terminal connector elements and terminal connector support means are also generally provided. Such terminal means are secured in an accessible position relative the core and coil arrangement.

Other important structures of the said electromagnetic device are clamping or retaining means mounted on the ends of the core and coil assembly to maintain the apparatus in assembly. In the manufacture of such apparatus, after same has been assembled the electromagnetic device is placed in a metallic canister and encapsulated with potting compound or the like along with other elements of the circuit (excepting of course, the load) with the leads protruding from the metal canister. The potted canister is thereafter sealed and mounted, for example, in a fixture having fluorescent lamps connected in circuit relationship therewith.

'The invention herein is directed to providing a single element having a two-fold function and relates to the clamping means and the terminal mounting means above described. Both functions of the invention most advantageously may be utilized with iron core elements other than the forced fit construction, i.e. that construction comprising an integral rectangular outer structure and an I- shaped center winding leg portion. Thus the invention is most advantageously utilized in connection with the T and 3,337,245 Patented June 4, 1968 F, T and L, C and I, and E and I arrangements and will be described in detail in connection with T and F constructions. Nevertheless, the invention may be quite useful when applied to forced fit construction but will not provide maximum benefits.

Heretofore, terminal connector mounting means comprised in most instances a member of fiberboard, cardboard or the like carrying metal terminal connecting members secured thereto by stapling or other well known methods. Such terminal connector mounting means were adapted to have the electrical winding extensions or taps as Well as the external lead means secured thereto and permanently joined in an electrical connection by soldering or other methods. The said terminal connector mounting means of the prior art were mounted directly upon the outer wrapper of the coils or immediately adjacent to said coils at the side portions of the core. A few turns of pressure sensitive tape were wound around both core, coil and terminal connector mounting means so as to secure same in place. Block members have been suggested which carry terminal connector means thereon and are secured at the sides of the core.

Disadvantages encountered with the above described terminal mounting means include: the fragility of the said mounting means, undue strain upon the electrical connections attributable to the position at which the said connections are required to be made, inconvenience and lack of facility in the making of the aforesaid electrical connections. Such means also were not economical in most cases.

Clamping means encountered in the prior art for mechanically holding the core and coil assembly together have most frequently taken the form of metallic clamps generally of spring steel. Such spring clamps have been adapted to fit tightly over each end portion of the core subsequent to the mounting of the coils thereon. Such clamps have certain disadvantages arising from their manner of construction and equally attributable to the metallic nature of the same. Regardless of the construction of the aforementioned metal clamps, all of the laminations forming the core may not be held rigidly enough to eliminate vibration during the operation of the electromagnetic device. This is usually caused by minor variations between dimensions of single laminations or groups so that clamping pressure is not uniformly applied to all of the said l'aminations. The said metallic clamps may contribute to high magnetic losses, formation of eddy currents, and the like causing power losses, hot spots and subsequent loss in efficiency of the device. A further disadvantage of considerable import lies in the substantial cost of such metallic clamps related to the unusual treatment and expensive material required therefor. The art has long, but unsucessfully, searched for clamping means which could be formed from non-metallic material but which still would have sufiicient strength to maintain the assembly rigidly whereby buzzing, stray magnetic fields, etc. would be substantially eliminated from said electromagnetic devices.

Accordingly, the principal o'bject of the invention is the provision of a retainer ring member of non-metallic material for clamping and retaining a core and coil assembly of the character described so as substantially to eliminate the above enumerated .disdvantages encountered in prior devices, and which provides a stronger, more secure, convenient and economical means for holding the laminations in assembly.

One method of preventing the vibrations which result in buzzing and like noises during operation of the electro magnetic device includes the application of thermosetting resinous materials, such as epoxy based resinous compositions, at the ends of the core parts so as to insure retention of each of the lamination parts in a substantially vibrationless assembly. The use of metallic clamps is not feasible because of substantial difliculties in the handling and affixing thereof over a core end to which said resinous material has been applied. Clamps heretofore available tend to move or slip off the cores prior to the curing. of the resinous material and hence the use of such resinous material, although quite advantageous for elimination of many disadvantages heretofore encountered, has been drastically curtailed.

Thus, another important object of the invention is the provision of non-metallic clamping means for a core and coil assembly of an electromagnetic device which comprises a ring member adapted to fit tightly on the end portions of said core and coil assembly in such a manner as to encircle same while exerting a clamping force upon each of the individual laminations, said ring member adapted advantageously to be utilized in conjunction with the application of synthetic thermosetting resinous materials so as to retain said assembly free from noise, vibration and the like.

A still further object of the invention is to provide a non-metallic retaining ring for a laminated transformer core which is formed of insulating material such is pressed fiber or paperboard, and which may be provided with a portion thereof of increased resiliency which will exert a clamping force on each of the laminations of said core regardless of discrepancies possibly encountered in the dimensions or positioning of said laminations.

The invention also has an equally important object thereof, the provision of a retainer ring for an electromagnetic device of the character described which will also function dually as a terminal connector mounting board, terminal connector means being provided which are adapted to be carried upon said retainer ring.

In connection with the last mentioned object of the invention, said terminal connector means contemplated by the invention enable the electrical connections between the coil ends and/ or taps and the other components of the electromagnetic device to be made without strain and stress upon said ends, taps or leads; and to be made at the ends of said core and coil arrangement.

A further object of the invention is to provide means upon the said retaining ring of the invention whereby the core and coil assembly may be inserted into a canister with the said assembly spaced from the floor of said canister, permitting the introduction of potting compound between the assembly and the canister floor. Such arrangement is believed to provide better heat conduction so that the overall operating temperature of the said electromagnetic device is well below the required maximum temperatures.

Other objects of the invention include the provision of various terminal connector devices, each adapted to be mounted upon the non-metallic retainer ring of the invention, the structure thereof permitting substantial economies to be made during the manufacture of the electromagnetic devices, particularly in the reduction of labor time consumed in making the necessary connections and the substantial reduction in the occurrence of faulty connections. In particular, it is one object of the invention to provide a terminal connector device in the form of a wire staple which may be secured by conventional stapling means, having feet clinched into one face of the ring and a closed loop formed on the other face to receive wires and terminal ends which may easily be soldered in permanent securement.

Many other objects and advantages of the invention will occur to the skilled artisan in this art as the description thereof ensues; in connection therewith, the drawings illustrate a preferred embodiment thereof. Although the invention is described with reference to a particular ballast device, it is believed that the invention has broader applications as will be evident from said description.

Referring to the drawing,

FIG. 1 is a perspective view of an electromagnetic device which has been constructed in accordance with the invention, the same being illustrated with one of the pair of non-metallic retaining ring members disposed in exploded relation at one end of the device.

FIG. 2 is a top plan view of the non-metallic retaining ring of the invention.

FIG. 3 is an exaggerated sectional view taken along line 33 of FIG. 2 and in the direction indicated by the arrows.

FIG. 4 is an exaggerated sectional view taken along line 44 of FIG. 2 and in the direction indicated by the arrows.

FIGS. 5, 6 and 7 are enlarged fragmentary perspective views of the non-metallic retainer ring of the invention illustrating modifications of the terminal connector structures installed thereon.

FIG. 8 is a sectional view taken through an electromagnetic device constructed in accordance with the invention, the view being at one end of the potted canister to show an end view of the internal assembly, a nonmetallic ring of modified construction being used in this embodiment.

FIG. 9 is a fragmentary top plan view of the same, with parts broken away to show the interior thereof.

FIG. 10 is an enlarged sectional view through the ring of FIGS. 8 and 9 through the terminal connector structures, looking down upon the same, before any wire leads are attached.

The invention will be described hereinafter with reference to an electromagnetic device commonly referred to as a ballast, said ballast being utilized to provide an electrical circuit for the starting and operation of gaseous discharge devices such as fluorescent lamps. In particular, the invention will be described as applied to those ballast devices having the shell type core construction other than those of the forced-core type, and which comprise a plurality of core parts having electrical windings mounted thereon. In order to retain the said construction in a rigid assembly, the invention contemplates the provision of a non-metallic retaining ring member preferably formed of pressed fiberboard, paperboard and like materials, which is adapted to receive the ends of the core therethrough. The retaining ring of the invention is particularly adapted for use in conjunction with a synthetic resinous cementitious material applied at the ends of the said device to form a vibration absorbing, strongly secured seal at said ends of the device. It should be pointed out and will be evident from the ensuing discussion that although the use of said synthetic resinous material is desirable and recommended, the retainer ring of the invention possesses sufiicient strength by itself to be of advantage to maintain the core assembly without the use of said resinous material.

The invention is characterized by the provision of some means to accommodate variations in core dimension so that substantially uniform pressure will be exerted on the faces of the cores, where such variations are manifest as unevenness. Said means may comprise extension portions or fingers along the engaging parts of the ring, so that undue pressure upon any one area will not distort the ring, and so that some resilience may be provided.

The invention further contemplates the provision of terminal connector means adapted to be mounted upon said retaining ring whereby said ring additionally functions as a terminal connector mounting board permitting the required electrical connections to be made at the ends of the device rather than at the sides thereof and eliminating the side mounting of heretofore encountered terminal connector mounting means. By side mounting it is intended to mean a terminal board mounted on the coil faces visible in FIG. 1.

. Attention is now directed to FIG. 1 wherein a transformer core and coil assembly 10 is illustrated. Said assembly 10 is illustrative of shell-type core construction which is formed of three core parts; namely, a pair of elongate F-s'haped leg members 12 and 14, and a central T-shaped leg 16. Each of the said parts 12, 14 and 16 is formed of a plurality of laminations stacked together, the laminations of each respective part being identical in configuration and substantially identical in dimension, each stack matching the other in height.

The core parts 12, 14 and 16 are arranged with the extensions 18 and 20 respectively in facing relationship one to the other and the central or T-shaped leg 16 interposed therebetween, the ends of said extensions 18 and 20 tightly abutting said central winding leg 16. A plurality of electric coils or windings 22 is mounted on the central winding leg 16 and said coils are disposed in the windows 24 and 26 for-med by extensions 28 and 30 of the core parts 12 and 14 when said parts are assembled, the extensions 28 and 30 forming shunt means for transformer 10 in the well known manner. Such coils 22 have wires 32 constituting coil ends and/or taps extending therefrom which are adapted to be connected in a predetermined relationship to form a circuit for the operation of a load, in this instance, a fluorescent lamp (not shown). Said wires may be held in place by tape 33.

As illustrated in FIG. 1, the lower end 13 of the assembly 10 is provided with a non-metallic retaining member constructed in accordance with the invention, shown installed thereon with the coil ends 32 electrically connected to terminal connector means 60 mounted upon said member 40 and with external lead means 42 also secured to said terminal connector means 60. The upper coil ends are shown in position to be electrically connected with the terminal connector means 60 carried by the non-metallic retainer ring 40 shown about to be forced over the upper end 15 of the assembly 10.

The non-metallic retainer ring 40 with which the invention is primarily concerned comprises a substantially rectangular fiat ring 44 having end portions 46 and 48 and elongate side portions 50 and 52. One of said side portions, such as portion 52, may be provided with a slightly wider median area 51 between the ends 4-6 and 48. The function of this median area 51 will be described below. The ring 44 has a central recess 54 which may be formed simultaneously with the forming of the ring 44, said recess being of an interior width, A, slightly larger than the maximum thickness dimension of the end 15 assembly 10 and has an interior length, B, slightly smaller than the maximum elongate dimension of the said end 15 of the assembly 10. A plurality of extension portions or fingers 56 are provided integral with the side portions 50 and 52 and extending inwardly into the recess 54. Such fingers 56 are spaced one from the other by notches 58 which form part of the recess 54. The distance between opposed fingers 56 defines said dimension A. Said last mentioned width dimension could also be expressed in terms of the height of the stack of laminations forming the transformer parts 12, 14 and 16.

The material comprising the retainer ring 40 preferably is chosen to be a crushable or compressible material, such .as compressed fiberboard or paperboard although synthetic plastic materials may be used with retention of the advantages of the structure. Said ring 40 may be stamped from sheet material of the character described in such a manner that the main ring body, that is the ends 46 and 48 and the side portions 50 and 52, are further compressed during the stamping process although this is not essential. By way of example, the finger portions 56 illustrated in FIG. 3 are shown to be slightly thicker than the said portion 52 and are disposed at an oblique angle relative the said side portion. The slightly greater resiliency of the fingers 56 obtained by the said additional compression of the material during formation of ring 40 above described enables additional pressure to be applied to all l-aminations forming the core parts in spite of probable slight dilferences in position and dimension between individual laminations. This additional resiliency is no- 6 wise to be considered as limiting to the invention but viewed only as one advantageous embodiment thereof. The method of formation of the fingers 56 is likewise not mandatory.

It is preferable and most advantageous to assemble the ring 40 over the end 15 of the transformer with the fingers 56 angled in a direction outward from the body of the transformer assembly 10. The purpose of this angular inclination of fingers 56 is to lead the ring 40 when it is engaged over the ends of the assembly 10. It is easier to force the ring 40 over the ends of the core assembly 10 with the said fingers 56 bent backwards so that there is some give. Thus when the ring is seated in its final position, as indicated by the lower portion of FIG. 1, any attempt to remove the ring is opposed by those angled portions 56 digging into the core parts, i.e. exerting substantial pressure thereon.

In connection with the assembly of the core and coil assembly 10 utilizing the non-metallic retainer ring 40 of the invention, it has been found that a synthetic resinous material may be applied over the ends of the core parts 12, 14 and 16. One such resinous material which has been found to be particularly effective comprises a low viscosity epoxy based resin which jells at room temperature and cures at an elevated temperature. This resin is preferably applied after the core parts have been forced through the ring 40; the free ends of the core parts being dipped into a solution of said resinous material. Of course, application of the resinous material by brushing or other means may be also effective. In this manner the retainer ring is reinforced in terms of its clamping capabilities and good noise reduction is achieved when the ballast is operated.

The ring 40 achieves its dual or second function as a terminal connector mounting board when terminal connector means 60 such as structures designated by reference character 62 in FIGS. 1, 2 and 3 are fastened or otherwise afiixed thereto along the outer periphery of said ring and along the uniform dimensioned side wall 50. In addition to the form of terminal connector means 60, the terminal connector means 60 adapted for installation upon said ring 40 may take the forms designated by reference characters 64 and 66 in FIG. 5, 68, 7t} and 72 in FIG. 6 and the reference characters 74, 76 and 78 in FIG. 7, the latter comprising various rivet-secured terminal connectors.

Looking at FIG. 4, there is illustrated a terminal connector 62 secured to the side wall 50 of ring 40. The terminal connector 62 comprises a U-shaped member of conductive metal having elongate arms 80 and 82 integral with a bridging portion 84. The bridging portion 84 is provided with a tongue member 86 spaced therefrom around which the coil end and/or tap 32 is adapted to be wound for electrical connection purposes. The distance between the arms 80 and 82 is chosen so that the portion 50 of the ring 40 may fit tightly therebetween. Arms 30 and 82 are provided with triangular shaped inwardly projecting members 87 which are adapted to dig into the surface of side 50 to hold the connector in position after same is forced thereon. A suitable clinching tool may be used for this.

The differences between terminal connector 62 and terminal connectors 64, 66, 68, 70 and 72 reside in the construction of the bridging member 84 and/or the wire support means disposed thereon. Terminal connector 64 is provided with a pair of oppositely directed tongue members 90 and 92, the free ends thereof being spaced from the plane of the bridging member from which they are formed at opposed edges thereof.

Terminal connector 66 is similar to terminal connector 62 except that upstanding lugs 94 are substituted for the tongue 86 and extend substantially perpendicular to the plane of said bridging member 84, the latter being imperforate. The coil ends 32 may be intertwined among said lugs 94 and permanent electrical connection made as by soldering. The lead wire 44 may be placed along the bridge portion 84 and the lugs 94 bent thereover, for example, by use of a pliers, and the result soldered or welded to form a permanent electrical connection.

Directing attention now to FIG. 6, terminal connector 68 is similar in construction to terminal connector 62 except that the tongue 86 has its free end facing in an opposite direction to that of tongue 86 of terminal connector 62. Terminal connector 70 has a bridge portion 84 including a pair of arcuate bridging members 85 and an oppositely curved central portion 89. The electrical connection is made therewith by threading a lead under either or both of the arcuate members 85, twisted therearound and soldering same. In terminal connector 72, a pair of upstanding hook members and 92' are provided integral with the edges of bridging member 84 and the free ends thereof facing one or the other. Utilizing the constructions embodied in terminal connectors 70 and 72, multiple connections to the same terminal post are facilitated.

Looking at FIG. 7, there are shown several examples of the rivet held and/or eyelet type terminal connector. To accommodate this type of terminal connector, the side 50 of ring 40 is provided with passageways adapted to accommodate a rivet therethrough. Terminal connector 74 comprises a hollow metallic rivet 95 through which a wire lead may be threaded. Terminal connector 76 has a hook-like member 96 secured to said ring member 40 by a similar hollow rivet 95'; and, in terminal connector 78, the said hook-like member 96 is replaced by a flattened member 97 having an eyelet 93 disposed therein. The latter two configurations, 76 and 78 also facilitate multiple lead connections.

The portion 51 of side 52 functions as a support for the core and coil assembly when the same is placed in a canister so as to enable the said assembly to rest slightly spaced from the floor of the canister. This enables potting compound to reach under the core and coil assembly eliminating commonly occurring voids or air pockets. In this manner the occurrence of hot-spots and the achievement of better heat conductivity between the core and coil assembly and the metallic canister is accommplished due to the presence of highly thermally conductive material therebetween without the presence of air-pockets or voids.

FIGS. 8, 9 and 10 illustrate a simplified but very effective form of the invention. In FIG. 8 there is illustrated a ballast 100 which is held in assembly by the nonmetallic ring 40 and another such ring not visible in this view. The parts of the core are here seen at 12, 14 and 16, the latter being the central winding leg. Core ends 18 and 20 abut and are clamped against the end of the central winding leg 16 by ring 40. The assembly is disposed in a canister 102, immersed in a potting compound 104 and the canister is covered by a metal cover plate 106. Load leads 42 emerge from the end wall 108 of the canister. Inside the canister 102, there may be disposed a capacitor 110 and some of the lead ends 32 may be connected therewith as well as with the load leads 42.

In this case the ring is fiat and has fingers 56 on the top and bottom of the central recess 54, these bearing against the stacks of laminations to hold same firmly. The bottom edge of ring 49 has a wide notch or recess 112 to give rise to feet 51 by means of which the entire transformer 100 is spaced above the floor 114 of the canister so that potting compound 194 is easily run in under the coils 22.

On its top side portion 50 the ring ring is provided with the terminal connectors 116. These are of wire, and are applied by a stapling apparatus. There are the feet 118 which are forced through the side portion 50 and clinched inward as at 120. The connectors are pinched at 122 to prevent their being pushed through the ring, and a full loop formed at 124.

The rings 40 provide ideal means to anchor and solder wire ends as shown, and are simple and strong.

In this form of the invention there is no provision for bending fingers 56. In forcing the ring upon the transformer ends, notches 126 help seat the same (as in the form previously described) and the fingers will yield to partially crush or collapse to accommodate variations in dimension. Some crushing is needed to assure that the ring is tightly in place.

The specific configurations, materials and other details of the invention were illustrated as preferred examples of the invention as applied to apparatus utilized in circuits for the starting and operation of gaseous discharge devices and are not intended to limit the invention to the said described apparatus and/or embodiments except as defined in the claims apended hereto. Many variations may be made in size, dimensions, configurations, materials and other specific details of the invention without departing from the scope thereof as defined in said appended claims.

What it is desired to secure by Letters Patent of the United States is:

1. In combination, a core retainer and a laminated transformer core, said retainer comprising, a non-metallic, frame-like planar body of generally rectangular configuration having inner edges defining a central opening accommodating a core end entirely therethrough with nonflexure of said body, at least a pair of proposed fingers formed integral with said body and extending interior of said opening, said fingers forcibly engaging said core laminations to clamp same in rigid assembly.

2. The combination as claimed in claim 1 in which said fingers partially are deformed in engagement with the core.

3. The combination as claimed in claim 1 in which the fingers are disposed at an oblique angle relative to said body.

4. The combination as claimed in claim 1 and electrical terminal connector means mounted on said body at selected locations spaced from said central opening.

5. The core retainer as claimed in claim 1 in which said body has a portion thereof extending outward along a long edge thereof opposite from the central opening.

6. In an electromagnetic core assembly which includes at least a pair of laminated core parts having portions thereof arranged in abutting relationship; the invention comprising, a non-flex clamp member of electrical insulating material having a fiat planar body of substantially rectangular frame configuration, said body having inner edges defining a central opening for accommodating the core parts entirely therethrough, said body having at least a pair of yieldable finger protrusions extending axially interior of said central opening and engagable tightly with said core parts for maintaining the assembly thereof immovable and terminal connector means mounted on said body spaced from the said inner edges.

7. The structure as claimed in claim 6 and, in combination therewith, a film of polymerized thermosetting resinous material at the abutting portions of the core parts and in permanent engagement with said clamp body.

8. A core retainer for a laminated transformer core comprising, a non-metallic frame-like flat planar body of generally rectangular configuration having inner edges defining a central opening to accommodate a core end entirely therethrough with non-flexure of said body, at least a pair of opposed fingers formed integral with said body and extending interior of said opening, said fingers forcibly engageable with said core to clamp same in rigid assembly, and electrical terminal connector means mounted on said body at selected locations spaced from said central opening, said terminal connector means comprising a U-shaped metallic member having a pair of arms and a bridging portion, means on said arms for permanently securing same upon said retainer ring and 9 1%) terminal connector mounting member, and wire gripping 2,563,105 8/1951 Epstein 336210 means formed on said bridging portion. 2,827,615 3/ 1958 Henderson 336-212 3,169,235 2/1965 Ouleita 336-210 References Cited UNITED STATES PATENTS 5 LARAMIE E. ASKIN, Primary Examiner. 1 997 641 4 1935 Isenberg 336 203 X E. GOLDBERG, Assistant Examiner.

2,459,943 1/1949 Jauss 336192 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,387,245 June 4, 1968 Eugene Czernobil It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 7, line 17, "one or the other'-' should read one the other line 42, "accommplished" should read accomplished line 69, "ring ring" should read ring Column 8, line 16, "apended" should read appended line 41, "The core retainer" should read The combination Signed and sealed this 28th day of October 1969.

(SEAL) Attest:

Edward M. Fletcher, Jr. WILLIAM E. SCHUYLER, JR.

Attesting Officer Commissioner of Patents 

8. A CORE RETAINER FOR A LAMINATED TRANSFORMER CORE COMPRISING, A NON-METALLIC FRAME-LIKE FLAT PLANAR BODY OF GENERALLY RECTANGULAR CONFIGURATION HAVING INNER EDGES DEFINING A CENTRAL OPENING TO ACCOMMODATE A CORE END ENTIRELY THERETHROUGH WITH NON-FLEXURE OF SAID BODY, AT LEAST A PAIR OF OPPOSED FINGERS FORMED INTEGRAL WITH SAID BODY AND EXTENDING INTERIOR OF SAID OPENING, SAID FINGERS FORCIBLY ENGAGEABLE WITH SAID CORE TO CLAMP SAME IN RIGID ASSEMBLY, AND ELECTRICAL TERMINAL CONNECTOR MEANS MOUNTED ON SAID BODY AT SELECTED LOCATIONS SPACED FROM SAID CENTRAL OPENING, SAID TERMINAL CONNECTOR MEANS COMPRISING A U-SHAPED METALLIC MEMBER HAVING A PAIR OF ARMS AND A BRIDGING PORTION, MEANS ON SAID ARMS FOR PERMANENTLY SECURING SAME UPON SAID RETAINER RING AND TERMINAL CONNECTOR MOUNTING MEMBER, AND WIRE GRIPPING MEANS FORMED ON SAID BRIDGING PORTION. 